Molecular Genetics of the Red Cell Membrane Skeleton

描述（由申请人提供）：本提案的长期目标是阐明涉及膜骨架蛋白编码基因表达的分子机制，特别是编码血影蛋白的基因，血影蛋白是红细胞和非红细胞膜骨架的重要成分。对这些基因的研究具有科学意义，因为这些基因在红细胞和非红细胞中产生的同种型的多样性。这种多样性提供了在分子水平上研究在专门组织中组织特异性基因表达的机制的机会，包括染色质结构的相关变化、选择性启动子的使用和调节以及组织特异性选择性剪接的调节。这些机制的详细分析，使用的基因家族的成员，结构上非常相似，但在不同的组织中的表达模式非常不同的行为，可以提供重要的见解在真核生物中的基因表达的分子生物学。此外，血影蛋白具有生物学和医学意义，因为红细胞基因的突变与遗传性溶血性贫血有关，并且因为非红细胞基因产物与一些重要的神经功能有关。拟议的实验包括：鉴定和表征调节红细胞β-血影蛋白基因的组织特异性转录的顺式决定簇;研究β-血影蛋白基因嵌入表达该基因的红细胞和肌肉细胞中的染色质结构;并研究转录后前体mRNA加工事件的分子机制，如选择性切割-多聚腺苷酸化和选择性剪接，导致在不同组织中产生不同的β-血影蛋白C-末端同种型。

DESCRIPTION (provided by applicant): This proposal has as its long-term objective the elucidation of molecular mechanisms involved in the expression of genes encoding proteins of the membrane skeleton, in particular the genes encoding the spectrins, important constituents of the membrane skeleton of erythrocytes as well as nonerythroid cells. Study of these genes is of scientific interest because of the diversity of isoforms that these genes produce in erythroid and nonerythroid cells. This diversity presents the opportunity to investigate at the molecular level mechanisms involved in tissue-specific gene expression in specialized tissues, including associated changes in chromatin structure, use and regulation of alternative promoters and regulation of tissue-specific alternative splicing. A detailed analysis of these mechanisms using members of a gene family that are structurally very similar, but behave very differently in their pattern of expression in various tissues, can provide important insights in the molecular biology of gene expression in eukaryotes. In addition, there is biological and medical interest in the spectrins because mutations in the erythroid gene are associated with hereditary hemolytic anemias, and because the non-erythroid gene products have been implicated in some important neurological functions. The proposed experiments include: identification and characterization of cis determinants that regulate the tissue specific transcription of the erythroid beta-spectrin gene; study of the chromatin structure in which the beta-spectrin gene is embedded in erythroid and muscle cells that express the gene; and study of the molecular mechanisms involved in the post-transcriptional pre-mRNA processing events, such as alternative cleavage-polyadenylation and alternative splicing, that result in the production of different C-terminal isoforms of beta-spectrin in different tissues.